With increasing miniaturization of sensors and sensor systems, for example in the form of a Micro-Electro-Mechanical System (MEMS), increasing importance has to be accorded to interference influence variables, for example on account of a temperature change.
A MEMS accommodated in a housing or an application-specific integrated circuit (ASIC) can be influenced by external influences. A MEMS is a component which combines one or more logic elements and a micromechanical structure in one chip. It can process mechanical and electrical information. ASICs are electronic circuits that are realized as integrated circuits. A MEMS comprises one or a plurality of sensors. The sensor or sensors is or are situated for example in direct proximity to one another and is or are accommodated in a common housing, which is also referred to as a package.
In a case where a plurality of sensors are accommodated in a common package, a mutual influencing of the sensors, for example as a result of a thermal power loss, can occur.
If, in an electronic circuit, a MEMS is situated for example alongside a power amplifier or in the vicinity of an antenna of a mobile telephone, then the measurement signal of the MEMS can be adversely influenced, that is to say that the measurement signal can be corrupted for example by the power amplifier or the antenna.
In this context, mention is also made of “XT” “X talk” or “cross talk”. This is a term that generally denotes the undesired influencing of signals which per se are independent of one another.
In particular, during the operation of further electronic components in an electronic component system, a power loss in the form of heat can occur. The emitted heat of one component or of a plurality of components can cause cross-talk with, or be transferred to, the MEMS, for example.
To put it another way, an environment of a sensor of a MEMS is heated as a result of the heat generation of one further component or a plurality of further components. A sensor in a housing (package) can reflect the activity of the at least one component. Ideally, no influencing of the sensor, for example of the MEMS sensor, by the external influences would occur.
If one further component is switched on, for example, then a power loss in the form of heat arises. The power loss is manifested in the form of heat generation, which can lead to a temperature increase in the environment of the at least one device after the at least one component has been switched on. On the other hand, when the at least one further component is switched off, a temperature reduction or a temperature decrease or cooling can occur in the environment of the at least one further device since power loss is no longer generated.
Consequently, a measurement signal provided by the MEMS is corrupted on account of the temperature influencing or temperature change. Said temperature change causes an undesired change in the output signal of a sensor.
The temperature change can lead to incorrect information at the output of the sensor. In this regard, by way of example, in the case of a microphone that is influenced by a temperature change, a heating power of less than 100 W can suffice to cause audible X talk (this may also be referred to as a thermoacoustic effect). The temperature change here is less than 1 mK and cannot usually be measured or used as an input for compensation of the temperature change. A signal purged of a thermal interference variable may be referred to in the present case as a thermal-X talk-compensated signal.
There is thus a need for a MEMS circuit and a method by means of which such temperature influencing or X talk can be kept within a predetermined tolerance range or can possibly even be minimized.